Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Engine (http://www.hotrodders.com/forum/engine/)
-   -   350 tunnel ram question? (http://www.hotrodders.com/forum/350-tunnel-ram-question-220955.html)

jlang 06-24-2012 09:57 PM

350 tunnel ram question?
 
Hey all, I just picked up an s10 with a Chevy 350. It has a mild build currently but I am looking to get more out of it. I have access to a dirt cheap high rise tunnel ram with dual 450 cfm carbs. Which brings me to my question. What kind of supporting mods would I need to run this setup? Could I run this on stock heads and bottom end? Or would I have to run its so lean it isn't worth it?

thanks, John

68NovaSS 06-24-2012 10:07 PM

Do you have enough compression and cam to support that much fuel delivery? Tell us more about what your mild build consists of. Tunnel rams can be run on the street, but tricky to tune. If you run this setup, only tune or make adjustments when the intake is at operating temp.

BigChevyFTW 06-24-2012 10:10 PM

to answer your question accurately we will need more information.

tunnel rams arent that expensive and unless your getting a super deal it might not be worth it because you will have to change things in the engine so it works in harmony or else it will suffer performance wise.

what is your goals?
What has been done to the engine?
what cam are you currently running?
have the heads had any work done to them?

the answers can help us help you so fill us in and we will do our best to help if we can.

jlang 06-24-2012 10:39 PM

It is a stock block and heads with performer intake and 650cfm carb. The P.O told me a mild cam and that's all, I am guessing its what ever size Schucks/ Oriellys' carries judging by the rest of what is on there. I can pick up the tunnel ram and carbs for $300. Right now I am just looking for more power without any head work or tearing into the bottom end at the moment. I have another major project at the moment and don't want this to become one.... yet.


thanks for your help, John

BigChevyFTW 06-24-2012 10:48 PM

for 300 thats not a bad deal!

listen to me when i tell you that you dont need a tunnelram to make big power from a 350

all that needs to be done to a 350 is 3 things

cam swap
intake and carb swap
ignition system msd distributor,ignition box and a blaster coil.

you can get over 400 hp by just changing the above mentioned parts

i have built over 30 small block chevys in the last 20 years and some of them i have made 700 hp with a stock block


i built a 450 hp chevy engine for a 69 chevelle for 1200 bucks and its all chrome you can see it on youtube type in bigchevyftw and youll see the car i also used the cam everyone on the internet says isnt a good performance cam yea the comp mutha thumpr cam you tell me if you think it dont perform
http://www.youtube.com/watch?v=03YfbbBTExo

cobalt327 06-25-2012 06:09 AM

Quote:

Originally Posted by jlang
It is a stock block and heads with performer intake and 650cfm carb. The P.O told me a mild cam and that's all, I am guessing its what ever size Schucks/ Oriellys' carries judging by the rest of what is on there. I can pick up the tunnel ram and carbs for $300. Right now I am just looking for more power without any head work or tearing into the bottom end at the moment. I have another major project at the moment and don't want this to become one.... yet.


thanks for your help, John

Offer the guy $250 for the TR, settle somewhere between that and his asking price. Put it away for a trade, or to use yourself, but I'd suggest you not use it w/a stock cam- there's just no need, although it could be made to run w/a stock cam.

The best money you can spend right now would be on better heads. Production Vortec heads would be worth a good amount of power, but the TR or the intake you now have won't fit on them because the bolt patterns are different. But there are relatively inexpensive aftermarket heads available that (along w/a cam change) would really wake that 350 up.

I'm guessing you have some sort of headers on this, but if not you need to get them.

1971BB427 06-25-2012 04:52 PM

I'd snatch that tunnel ram and carbs up quickly, even though I wouldn't use it on your fairly stock engine! It's an easy money maker, or to use when you've got the itch to build your engine further.
I've had a few tunnel rammed engines (mostly SBC, one BBC) and they for the most part were not a huge deal to tune. The first one taught me patience though, and from there I've learned and it made susequent engines and TR's easier to tune.
I warned my friend about tunnel rams when he asked me to help with the 350 in his '56 Chevy, but he insisted on wanting it for looks. I was shocked when we installed the Weiand tunnel ram and twin 500 Edelbrocks on a failry mild 350, with a middle sized Thumpr cam and it purred like a kitten! I was even a little irritated knowing what I've gone through on some to get them running as well.
My present car is a Holley Pro Dominator tunnel ram with twin 450's on a .040" 327. It's not super radical, but well built, and I had a little tuning to get things responding well. Changed accelerator pumps/cams, squirters, jets, power valves, and fooled with the timing. It starts and runs excellent now, but it did take some tinkering.

L79vette 06-25-2012 07:27 PM

[QUOTE=BigChevyFTW]for 300 thats not a bad deal!

listen to me when i tell you that you dont need a tunnelram to make big power from a 350

all that needs to be done to a 350 is 3 things

cam swap
intake and carb swap
ignition system msd distributor,ignition box and a blaster coil.

you can get over 400 hp by just changing the above mentioned parts

QUOTE]

Presumably the OP has smog heads (with the terrible rectangular combustion chamber) and 8.5:1 compression (maybe 8:1 depending on deck & head gasket thickness). How can you make >400HP with that compression and those heads? I would expect to get no more than about 320HP.

Also, are you saying you can get there without headers, or just left it off the list?

L79vette 06-25-2012 07:35 PM

Quote:

Originally Posted by jlang
Hey all, I just picked up an s10 with a Chevy 350. It has a mild build currently but I am looking to get more out of it. I have access to a dirt cheap high rise tunnel ram with dual 450 cfm carbs. Which brings me to my question. What kind of supporting mods would I need to run this setup? Could I run this on stock heads and bottom end? Or would I have to run its so lean it isn't worth it?

thanks, John

You can run it on the stocker. Is this an automatic? Stock stall? What rear end gears?

While you can run the TR on the basically stock motor, you will lose torque down low compared to a dual plane. I have been running them on the dyno at lower RPM as part of a project, and they are down on torque and have crummy response and really lousy fuel economy due to bad fuel distribution when running on the primaries. Once you get up to 3000RPM, they are better than anything else and just keep climbing.

If you have a stock stall and highway-friendly gears, you are not going to like the TR.

jlang 06-26-2012 06:09 PM

Thanks for all the help everyone. I think I will pick it up to hold onto for when I do a big build but for now I wont be using it. Bigchevy if you don't mind me asking what intake manifold, carb and cam were you using to make 400hp?

Thanks again, John

Jake_Dragon 06-26-2012 06:31 PM

I run a TR on my 350 in my Vette. I have two 390 Holley carbs.
It looks great, sounds great but anything under 3000 RPM is just noise out the exhaust. It doesn't start making power till around 2800 RPM

Now its isn't exactly anemic at low RPMs but if you want to impress anyone you are going to want to do it above 3000 RPM, for that you need to have a cam and heads that will breath enough to support the intake.

My 350 has a nice street/strip cam and roller rockers. It has had a nice port and polished job on the heads.
Headers and side pipes. It breaths pretty good.

I love the car and the TR works ok for around town driving but the MPG sucks.

http://i550.photobucket.com/albums/i...h_DSCF0732.jpg

jlang 06-26-2012 06:34 PM

Do camel hump heads flow enough for a tunnel ram? I don't know anything about them I've just heard they are really good.

F-BIRD'88 06-27-2012 12:03 PM

What is the casting number on the heads?
Can be a good choice. Sort of a dimaond in the rough.
Much better with porting.
Many of these old 30-40 yr old heads are not worth rebuilding.
Often worth more sold off to collectors stock eliminator racers
Especially in non cracked unmolested "stock" form.
to fund better modern aftermarket heads.
You can build a really good tunnel ram for the street but stock low perf stuff is going to kill the deal.

Stock low perf heads, low stock compression, small wimpy cams, small carbs
cripple a tunnel ram.
buy the t ram and pass on the carbs.
tuck it away and gain more knowledge on building such motors
get a good plan and go for it.
Here is a good example of a rockin street strip T ram motor. 10:1 cr
for pump gas. 550+hp
http://www.hotrod.com/techarticles/e...plate_systems/

plan on getting a 3500+ stall converter and 4.10+ gears.

here is the index of the this three part 355 SBC w tunnel ram engine build up.
http://www.hotrod.com/techarticles/i..._anvil_series/
read it know it there will be a test. :thumbup:

These tunnel ram motors have very good drivability for a hot rod type motor when done correctly. Ditch the 450cfm carbs. Do not buy small carbs if you want real horsepower.
The only small cfm carbs I would use are the 500cfm edelbrocks.
I prefer the 750's for a motor like this.

A tunnel ram motor needs a longer warm up time for street driving than a motor with a single 4 bbl manifold. Takes longer to get some heat in the manifold runners for good fuel vapourization etc. The carb tuning require3d is a bit more advanced.

1971BB427 06-27-2012 03:10 PM

Quote:

Originally Posted by jlang
Do camel hump heads flow enough for a tunnel ram? I don't know anything about them I've just heard they are really good.

Here's a picture of my setup, complete with cc'd camel hump 2.02 heads:
http://img.photobucket.com/albums/v6...y/DSCF3414.jpg

With 3.73 gears and a TH350 with 2000 stall it yanks the wheels off the ground if I hit it hard taking off. A tunnel ram can and does make good low end power if tuned correctly, and the right cam/pistons used. My cam is an Isky 270 mega cam, with flat top 9.5:1 pistons. The car is about 2500 lbs., and M&H drag radials on the rear.

jlang 06-27-2012 05:43 PM

Alright, I just bought a 327. I want to run the Tunnel Ram since these have high compression from what I've been able to find 10.5:1. If Im wrong please tell me. I've heard these had really good heads but I don't remember the name. Would it be better to use the stock heads or change to Camelhumps? I'm still very new to engine building, would someone please explain how to calculate what camshaft to use for my application. Thanks again for helping me with all my questions, I'm just getting into small block chevy's and appreciate the help.

, John


All times are GMT -6. The time now is 05:44 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.